JP2015078348A - Pressure-sensitive adhesive sheet for fastening polishing pad - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polishing pad-fastening pressure-sensitive adhesive sheet capable of tightly fastening a polishing pad.SOLUTION: The present invention provides a polishing pad-fastening pressure-sensitive adhesive sheet. A pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet comprises a styrene-based or conjugated diene-based block copolymer, and terpene phenol resin as tackifier resin. The pressure-sensitive adhesive face exhibits a 180° peel strength of 30 N/20 mm or greater to a stainless steel plate.

Description

  The present invention relates to an adhesive sheet used for fixing a polishing pad.

  High surface smoothness in liquid crystal glass, silicon wafers, hard disks and the like is generally realized by polishing. Polishing in this technique is performed by, for example, setting an object to be polished in a polishing apparatus and pressing a polishing pad attached to a polishing apparatus surface plate against the object while supplying a polishing liquid containing abrasive grains. This is done by moving both of the polishing pads relative to the surface of the object. The polishing pad used for the polishing is usually attached and fixed to a polishing apparatus surface plate using an adhesive. However, adhesives have problems in terms of workability such as time-consuming drying and solvent components volatilizing during drying. Therefore, mounting and fixing using an adhesive instead of an adhesive has been studied. For example, Patent Documents 1 and 2 are cited as documents disclosing the prior art using an adhesive sheet as the polishing pad fixing means.

JP 2012-57135 A JP 2012-102165 A

  The pressure-sensitive adhesive sheet used for mounting and fixing the polishing pad is required to have an ability to adhere well to the polishing pad. However, the adhesive force of the conventional pressure-sensitive adhesive sheet to the polishing pad has not been sufficient. For example, in a situation where there is a request to reduce the frequency of replacement of the polishing pad by extending the period of use of the polishing pad from the viewpoint of productivity improvement or cost reduction, it adheres more firmly to the polishing pad throughout the period of use. It would be beneficial if an adhesive sheet to be provided was provided.

  This invention is made | formed in view of the said conventional situation, and it aims at providing the adhesive sheet for polishing pad fixing which can fix a polishing pad firmly.

  According to the present invention, an adhesive sheet for fixing a polishing pad is provided. This pressure-sensitive adhesive sheet includes a pressure-sensitive adhesive layer constituting the pressure-sensitive adhesive surface of the pressure-sensitive adhesive sheet. Moreover, the said adhesion surface shows 180 degree peel strength of 30 N / 20mm or more with respect to a stainless steel plate. The pressure-sensitive adhesive sheet exhibiting the above peeling strength (vs. SUS adhesive strength) can be firmly bonded to the polishing pad. Therefore, according to this invention, the adhesive sheet especially suitable for a polishing pad fixed use is provided. The pressure-sensitive adhesive sheet disclosed herein can exhibit a high level of adhesive force that could not be realized in the past with respect to hard urethane polishing pads (for example, foamed polyurethane polishing pads). Polyurethane-based polishing pad) It is particularly preferably used for fixing.

  In a preferred embodiment of the pressure-sensitive adhesive sheet disclosed herein, the pressure-sensitive adhesive layer contains a block copolymer of a monovinyl-substituted aromatic compound and a conjugated diene compound as a base polymer. Among these, the base polymer is preferably a styrenic block copolymer.

  In a preferred embodiment of the pressure-sensitive adhesive sheet disclosed herein, the pressure-sensitive adhesive layer contains a tackifier resin. Moreover, it is preferable that the said tackifying resin contains high softening point resin whose softening point is 120 degreeC or more. Further, the high softening point resin preferably contains a terpene phenol resin. Further, the tackifying resin preferably contains a low softening point resin having a softening point of less than 120 ° C.

  In a preferred embodiment of the pressure-sensitive adhesive sheet disclosed herein, the base material, the first pressure-sensitive adhesive layer as the pressure-sensitive adhesive layer provided on one surface of the base material, and the other surface of the base material are provided. A double-sided pressure-sensitive adhesive sheet. In the double-sided pressure-sensitive adhesive sheet, the pressure-sensitive adhesive surface of the first pressure-sensitive adhesive layer is preferably attached to a polishing pad, and the pressure-sensitive adhesive surface of the second pressure-sensitive adhesive layer is preferably attached to a polishing apparatus surface plate.

  Moreover, according to this invention, the polishing pad by which the adhesive sheet (adhesive sheet for polishing pad fixation) disclosed here was affixed is provided. One surface of the polishing pad is bonded to the pressure-sensitive adhesive surface of the pressure-sensitive adhesive sheet. In a preferred embodiment, the pressure-sensitive adhesive sheet is configured as a double-sided pressure-sensitive adhesive sheet, and the pressure-sensitive adhesive surface (second pressure-sensitive adhesive surface) opposite to the pressure-sensitive adhesive surface (first pressure-sensitive adhesive surface) bonded to the polishing pad is polished. It may be an adhesive surface that is affixed to the apparatus surface plate.

It is a typical side view showing an example of application of an adhesive sheet for polishing pad fixation concerning one embodiment. It is typical sectional drawing which shows the structure of the adhesive sheet (double-sided adhesive sheet with a base material) which concerns on one Embodiment. It is typical sectional drawing which shows the structure of the adhesive sheet (base-material-less double-sided adhesive sheet) which concerns on other embodiment. It is typical sectional drawing which shows the structure of the adhesive sheet (single-sided adhesive sheet with a base material) which concerns on other embodiment. It is explanatory drawing which shows typically the measuring method of shear adhesive force.

  Hereinafter, preferred embodiments of the present invention will be described. Note that matters other than matters specifically mentioned in the present specification and necessary for the implementation of the present invention can be grasped as design matters of those skilled in the art based on the prior art in this field. The present invention can be carried out based on the contents disclosed in this specification and common technical knowledge in the field. In the following drawings, members / parts having the same action are described with the same reference numerals, and redundant descriptions may be omitted or simplified. In addition, the embodiment described in the drawings is schematically illustrated in order to clearly explain the present invention, and does not accurately represent the size and scale of the pressure-sensitive adhesive sheet actually provided as a product.

In this specification, the “pressure-sensitive adhesive” refers to a material that exhibits a soft solid (viscoelastic body) state in a temperature range near room temperature and has a property of easily adhering to an adherend by pressure. The adhesive here is generally defined as “CA Dahlquist,“ Adhesion: Fundamental and Practice ”, McLaren & Sons, (1966) P. 143”, and generally has a complex tensile modulus E ^* (1 Hz). <10 < ⁷ > dyne / cm < ² > material (typically a material having the above properties at 25 [deg.] C.). The “base polymer” of the pressure-sensitive adhesive is the main component (that is, 50% by mass of the rubber-like polymer) of the rubber-like polymer (polymer exhibiting rubber elasticity in the temperature range near room temperature) contained in the pressure-sensitive adhesive. Component which occupies the above).

<Applicable items for adhesive sheet>
The pressure-sensitive adhesive sheet disclosed herein is a pressure-sensitive adhesive sheet used for fixing a polishing pad. The polishing pad to which the pressure-sensitive adhesive sheet disclosed herein is attached is not particularly limited. For example, urethane foam (foamed polyurethane), polyolefin foam (foamed polyolefin), or other foamed resin-based polishing pads, or non-foamed Resin-based polishing pads and non-woven polishing pads can be used. You may have a laminated structure containing at least one layer of the above-mentioned polishing pad. The pressure-sensitive adhesive sheet disclosed herein is preferably used for fixing a urethane foam polishing pad. Although not particularly limited, for example, it is disclosed herein for a urethane foam-based polishing pad having a density of 0.3 to 1.2 g / cm ³ (typically 0.4 to 1.0 g / cm ³ ). A pressure-sensitive adhesive sheet can be preferably applied. Although there is no restriction | limiting in particular also about the hardness (JIS K6400-2 (2004) A method) of the said polishing pad, with respect to what has a hardness of about 60-120N (typically 70-100N) here. The disclosed adhesive sheet is preferably affixed. The polishing pad may be one in which abrasive grains are fixed in the pad.

  A preferred application example of the pressure-sensitive adhesive sheet disclosed herein is shown in FIG. As shown in FIG. 1, the adhesive sheet 1 has the form of a double-sided adhesive sheet having adhesive surfaces on both sides. Specifically, the pressure-sensitive adhesive sheet 1 includes a base material 15, a first pressure-sensitive adhesive layer 11 disposed on one surface of the base material 15, and a second pressure-sensitive adhesive layer disposed on the other surface of the base material 15. 12. An adhesive surface (first adhesive surface) 11 </ b> A of the first adhesive layer 11 is attached to the back surface 30 </ b> B of the polishing pad 30. The pressure-sensitive adhesive surface (second pressure-sensitive adhesive surface) 12 </ b> A of the second pressure-sensitive adhesive layer 12 is affixed to the surface 50 </ b> A of the polishing apparatus surface plate 50 provided in the polishing apparatus 40. In this way, the polishing pad 30 is fixed to the polishing apparatus surface plate 50 via the adhesive sheet 1.

  In the polishing using the polishing pad 30 as described above, for example, the polishing surface of the polishing pad 30 fixed to the polishing apparatus surface plate 50 in a state where a polishing liquid (not shown) is supplied with the rotation of the rotating shaft A. This is performed by pressing 30A against an object to be polished (not shown). After being used for a predetermined period, the polishing pad 30 is removed from the polishing apparatus base plate 50 (typically, removed between the polishing apparatus base plate 50 and the second adhesive surface 12A) and replaced with a new polishing pad. . Therefore, the pressure-sensitive adhesive sheet applied for the above-mentioned use (polishing pad fixing use) has a property of firmly adhering the polishing pad for a predetermined period of time and a property that the adhesive property does not deteriorate in the polishing environment (for example, low pH or high pH It is desirable to have properties such as the property that the adhesive properties are not deteriorated by the polishing liquid (chemical resistance). Moreover, it is preferable that the adhesive sheet disclosed here has a size suitable for the size of a polishing pad or a polishing apparatus surface plate that tends to be enlarged from the viewpoint of improving productivity. As such an adhesive sheet, for example, an adhesive sheet having a width of about 600 to 2500 mm (for example, 600 to 2500 mm, typically 1050 to 2500 mm) can be preferably used.

<Structural example of adhesive sheet>
The pressure-sensitive adhesive sheet disclosed herein (which may be in a long form such as a tape) may be, for example, in the form of a double-sided pressure-sensitive adhesive sheet having the cross-sectional structure shown in FIG. The double-sided pressure-sensitive adhesive sheet 1 includes a base material 15 and a first pressure-sensitive adhesive layer 11 and a second pressure-sensitive adhesive layer 12 that are respectively supported on both surfaces of the base material 15. More specifically, the first pressure-sensitive adhesive layer 11 and the second pressure-sensitive adhesive layer 12 are provided on the first surface 15A and the second surface 15B (both non-peelable) of the base material 15, respectively. As shown in FIG. 2, the double-sided pressure-sensitive adhesive sheet 1 before use (before being attached to an adherend) is wound in a spiral shape with the front surface 21A and the back surface 21B overlapped with a release liner 21 that is a release surface. It can be in the form of In the double-sided pressure-sensitive adhesive sheet 1 in this form, the surface of the second pressure-sensitive adhesive layer 12 (second pressure-sensitive adhesive surface 12A) is peeled off by the front surface 21A of the release liner 21, and the surface of the first pressure-sensitive adhesive layer 11 (first pressure-sensitive adhesive surface 11A) is peeled off. The liner 21 is protected by the back surface 21B. Alternatively, the first adhesive surface 11A and the second adhesive surface 12A may be protected by two independent release liners.

  The technology disclosed herein is preferably applied to a double-sided pressure-sensitive adhesive sheet with a substrate as shown in FIG. 2, and a double-sided pressure-sensitive adhesive sheet 2 having no base material (that is, having no base material) as shown in FIG. It can also be applied to. As shown in FIG. 3, for example, the double-sided pressure-sensitive adhesive sheet 2 before use has at least the first pressure-sensitive adhesive surface 11A and the second pressure-sensitive adhesive surface 11B of the substrate-less pressure-sensitive adhesive layer 11 on the surface (front surface) of the pressure-sensitive adhesive layer May be protected by release liners 21 and 22 that are release surfaces. Alternatively, the release liner 22 is omitted, and the release liner 21 having both sides of the release surface is used, and this and the adhesive layer 11 are overlapped and wound into a spiral shape, whereby the second adhesive surface 11B is released into the release liner. 21 may be in contact with the back surface of 21 and protected.

  As shown in FIG. 4, the technology disclosed herein is also a single-sided adhesive type substrate including a substrate 15 and an adhesive layer 11 supported on the first surface (non-peeling surface) 15 </ b> A of the substrate 15. The adhesive sheet 3 can also be applied. For example, as shown in FIG. 4, the pressure-sensitive adhesive sheet 3 before use has a release liner in which the surface (adhesive surface) 11 </ b> A of the pressure-sensitive adhesive layer 11 is at least the surface (front surface) on the pressure-sensitive adhesive layer side. 21 may be the protected form. Alternatively, the release liner 21 is omitted, and the first adhesive surface 11A is the second of the substrate 15 by winding the adhesive sheet 3 with the substrate using the substrate 15 having the second surface 15B as the release surface. It may be in a form protected against the surface 15B. When such a single-sided pressure-sensitive adhesive sheet is used for fixing the polishing pad, the substrate-side surface is fixed to the polishing apparatus surface plate or the like by another fixing means (for example, an adhesive).

<Characteristics of adhesive sheet>
The pressure-sensitive adhesive sheet disclosed herein has a pressure-sensitive adhesive surface of the pressure-sensitive adhesive layer constituting the pressure-sensitive adhesive sheet (in the case of a double-sided pressure-sensitive adhesive sheet, preferably only the pressure-sensitive adhesive surface (first pressure-sensitive adhesive surface) of the first pressure-sensitive adhesive layer) is 30 N / 20 mm. It is characterized by showing the above 180-degree peel strength (also referred to as “vs. SUS adhesive strength”). The pressure-sensitive adhesive sheet exhibiting SUS adhesive strength is particularly suitable for fixing the polishing pad because it adheres firmly to the polishing pad. The SUS adhesive strength is preferably 32 N / 20 mm or more, and more preferably 34 N / 20 mm or more. The pressure-sensitive adhesive sheet according to a particularly preferred embodiment may have a SUS adhesive strength of 35 N / 20 mm or more (for example, 36 N / 20 mm or more). The 180-degree peel strength is 30 minutes under the environment of 23 ° C. and 50% RH by reciprocating a 2 kg roller on the surface of a stainless steel (SUS) plate having the adhesive surface as an adherend. After being allowed to stand, it is measured under conditions of a tensile speed of 300 mm / min according to JIS Z0237. More specifically, the adhesion to SUS is measured according to the method described in Examples described later.

  When the pressure-sensitive adhesive sheet disclosed herein is a double-sided pressure-sensitive adhesive sheet, the SUS adhesive strength of the pressure-sensitive adhesive surface (second pressure-sensitive adhesive surface) of the second pressure-sensitive adhesive layer is 10 N / 20 mm or more (for example, 12 N / 20 mm or more, typically Is preferably 16 N / 20 mm or more. The pressure-sensitive adhesive sheet having the SUS adhesive force adheres well to a polishing apparatus surface plate (typically, a polishing apparatus surface plate whose surface to be bonded is made of metal). If the adhesive strength is too large, the removal workability when replacing the polishing pad may be reduced. Therefore, the SUS adhesive strength is 30 N / 20 mm or less (for example, 25 N / 20 mm or less, typically 20 N / 20 mm). Or less).

  The pressure-sensitive adhesive sheet disclosed herein has the pressure-sensitive adhesive surface of the pressure-sensitive adhesive layer constituting the pressure-sensitive adhesive sheet (in the case of a double-sided pressure-sensitive adhesive sheet, preferably only the pressure-sensitive adhesive surface (first pressure-sensitive adhesive surface) of the first pressure-sensitive adhesive layer) It is preferable that the SUS adhesive strength is exhibited after immersion in a NaOH aqueous solution at the same level or higher than the SUS adhesive strength. Here, “SUS adhesive strength after immersion in NaOH aqueous solution” means 1 kg of a 2 kg roller on the surface of a stainless steel (SUS) plate having the adhesive surface as an adherend in an environment of 23 ° C. and 50% RH. It refers to the adhesive strength against SUS measured after being reciprocated and pressure-bonded and immersed in an aqueous NaOH solution adjusted to pH 11 at 50 ° C. for 3 days. The pressure-sensitive adhesive sheet exhibiting SUS adhesive strength after immersion in an aqueous NaOH solution is excellent in chemical resistance and is particularly suitable for fixing a polishing pad that can be exposed to a polishing liquid. Further, the SUS adhesive strength after immersion in the NaOH aqueous solution is usually suitably 25 N / 20 mm or more (for example, 28 N / 20 mm or more), preferably 30 N / 20 mm or more, and preferably 35 N / 20 mm or more. It is more preferable. The pressure-sensitive adhesive sheet according to a particularly preferable embodiment may have a SUS adhesive strength after immersion in the NaOH aqueous solution of 40 N / 20 mm or more (for example, 45 N / 20 mm or more, typically 55 N / 20 mm or more). Most preferably, the SUS adhesive strength after immersion in the NaOH aqueous solution is 60 N / 20 mm or more. More specifically, the SUS adhesive strength after immersion in the NaOH aqueous solution is measured according to the method described in Examples described later.

  The pressure-sensitive adhesive sheet disclosed herein is a pressure-sensitive adhesive sheet in which the ratio (PS2 / PS1) of the SUS pressure-sensitive adhesive force (PS2) after immersion in the NaOH aqueous solution to the SUS pressure-sensitive adhesive strength (PS1) is 1 or more. Is preferred. An adhesive sheet satisfying the above ratio (PS2 / PS1) tends to be more excellent in chemical resistance. The ratio (PS2 / PS1) is preferably 1.2 or more (for example, 1.5 or more, typically 1.8 or more).

  In a preferred embodiment, the pressure-sensitive adhesive sheet disclosed herein has a pressure-sensitive adhesive surface of the pressure-sensitive adhesive layer constituting the pressure-sensitive adhesive sheet (preferably both pressure-sensitive adhesive surfaces in the case of a double-sided pressure-sensitive adhesive sheet) on a phenol resin plate as an adherend. Then, a 2 kg roller was reciprocated once with a bonding area of 10 mm in width and 20 mm in length, pressed down, left in an environment of 40 ° C. and left for 30 minutes, then applied with a load of 500 g and 1 in the same environment. In the constant load peeling test that is allowed to stand for a period of time, the time from when the load is applied until the pressure-sensitive adhesive sheet is peeled off from the adherend and dropped may be one hour or longer. A pressure-sensitive adhesive sheet having both the above characteristics and a pressure-sensitive adhesive force equal to or higher than the predetermined value can be a high-performance pressure-sensitive adhesive sheet in which both the pressure-sensitive adhesive force and the cohesive force are highly compatible. In a more preferred embodiment, in the constant load peel test, the displacement distance (mm) of the pressure-sensitive adhesive sheet 1 hour after the application of the load is 3 mm or less (for example, 1 mm or less, typically 0.5 mm or less). possible.

  In a preferred embodiment, the pressure-sensitive adhesive sheet disclosed herein has a liner peeling force (peeling strength against a release liner) on the pressure-sensitive adhesive surface of the pressure-sensitive adhesive layer constituting the pressure-sensitive adhesive sheet (preferably both pressure-sensitive adhesive surfaces in the case of a double-sided pressure-sensitive adhesive sheet). Can be less than 1 N / 50 mm (eg, 0.5 N / 50 mm or less, typically 0.4 N / 50 mm or less). A pressure-sensitive adhesive sheet satisfying this characteristic is excellent in the workability of pasting because the release liner can be easily removed. Considering that the workability may be lowered if the release force is too small, the liner release force is preferably about 0.01 N / 50 mm or more. The liner peeling force may be measured according to the following method.

[Liner peeling force]
A double-sided pressure-sensitive adhesive sheet prepared by bonding a release liner using a hand roller in an environment of a temperature of 23 ° C. and RH of 50% is prepared. This double-sided PSA sheet with a release liner is cut into a size of 50 mm in width and about 20 cm in length to obtain a measurement sample. The measurement sample is applied with a load of 1 kg in an environment of 100 ° C. for 1 hour, and then held in an environment of 23 ° C. and RH 50% for 1 hour. Using a tensile tester, the stress was measured when the release liner was peeled off under the conditions of 23 ° C., RH 50%, peeling angle 180 °, and tensile speed 300 mm / min, and the maximum value was peeled off. Strength (N / 50 mm width).

<Base polymer>
The pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet disclosed herein (which can also be grasped as the solid content of the pressure-sensitive adhesive composition) is known as an acrylic, rubber-based, It may contain one or more of various polymers such as polyester, urethane, polyether, silicone, polyamide, and fluorine. Especially, it is preferable that an adhesive is a rubber-type adhesive. The rubber-based pressure-sensitive adhesive refers to a pressure-sensitive adhesive containing a rubber-based polymer as a base polymer. Examples of the rubber-based polymer include natural rubber, styrene butadiene rubber (SBR), acrylonitrile butadiene rubber (NBR), isoprene rubber, chloroprene rubber, polyisobutylene, butyl rubber, and recycled rubber. These can be used alone or in combination of two or more.

  The pressure-sensitive adhesive in the technology disclosed herein is preferably a rubber-based pressure-sensitive adhesive containing a block copolymer of a monovinyl-substituted aromatic compound and a conjugated diene compound as a base polymer. Here, “a block copolymer of a monovinyl-substituted aromatic compound and a conjugated diene compound” is a segment having a monovinyl-substituted aromatic compound as a main monomer (a copolymerization component exceeding 50% by mass; the same shall apply hereinafter). (Hereinafter also referred to as “A segment”) and a polymer having at least one segment having a conjugated diene compound as a main monomer (hereinafter also referred to as “B segment”). In general, the glass transition temperature of the A segment is higher than the glass transition temperature of the B segment. As a typical structure of such a polymer, a triblock copolymer (ABA structure triblock) having A segments (hard segments) at both ends of a B segment (soft segment), one A Examples thereof include a diblock structure copolymer (A-B structure diblock body) composed of a segment and one B segment.

  The monovinyl substituted aromatic compound refers to a compound in which one functional group having a vinyl group is bonded to an aromatic ring. A typical example of the aromatic ring is a benzene ring (which may be a benzene ring substituted with a functional group having no vinyl group (for example, an alkyl group)). Specific examples of the monovinyl-substituted aromatic compound include styrene, α-methylstyrene, vinyl toluene, vinyl xylene and the like. Specific examples of the conjugated diene compound include 1,3-butadiene and isoprene. Such a block copolymer can be used for a base polymer individually by 1 type or in combination of 2 or more types.

  The A segment (hard segment) in the block copolymer has a copolymerization ratio of 70% by mass or more (more preferably 90% by mass or more) of the monovinyl-substituted aromatic compound (two or more types can be used in combination). It may be substantially 100% by mass). The B segment (soft segment) in the block copolymer has a copolymerization ratio of the conjugated diene compound (two or more can be used in combination) of 70% by mass or more (more preferably 90% by mass or more). It may be 100% by mass). According to such a block copolymer, a higher performance pressure-sensitive adhesive sheet can be realized.

  The block copolymer may be in the form of a diblock body, a triblock body, a radial body, a mixture thereof, and the like. In the triblock body or radial body, it is preferable that an A segment (for example, a styrene block) is arranged at the end of the polymer chain. This is because the A segments arranged at the ends of the polymer chains are likely to gather to form a domain, thereby forming a pseudo cross-linked structure and improving the cohesiveness of the pressure-sensitive adhesive.

  As the block copolymer in the technology disclosed herein, the diblock ratio is 30% by mass or more (more preferably 40% by mass or more, more preferably 50% by mass or more) from the viewpoint of peel strength with respect to the adherend. Particularly preferably, 60% by mass or more, typically 65% by mass or more) can be preferably used. From the viewpoint of peel strength, a block copolymer having a diblock ratio of 70% by mass or more is particularly preferable. From the viewpoint of cohesion and the like, a block copolymer having a diblock body ratio of 90% by mass or less (more preferably 85% by mass or less, for example, 80% by mass or less) can be preferably used. For example, a block copolymer having a diblock ratio of 60 to 85% by mass is preferable, and a block copolymer having a diblock ratio of 70 to 85% by mass (for example, 70 to 80% by mass) is more preferable.

  When the pressure-sensitive adhesive disclosed here is a rubber-based pressure-sensitive adhesive, the amount of the polymer other than the rubber-based polymer is appropriately 50 parts by mass or less, preferably 30 parts by mass per 100 parts by mass of the base polymer. Hereinafter, it is more preferably 10 parts by mass or less (for example, 5 parts by mass or less). The technology disclosed herein is an embodiment in which the base polymer of the pressure-sensitive adhesive is substantially composed only of a rubber polymer (for example, an embodiment in which the content of the rubber polymer per 100 parts by mass of the base polymer is 99 to 100 parts by mass) ).

<Styrenic block copolymer>
In a preferred embodiment of the technology disclosed herein, the base polymer is a styrenic block copolymer. Here, the “styrene block copolymer” means a polymer having at least one styrene block. The styrene block refers to a segment having styrene as a main monomer. A segment consisting essentially of styrene is a typical example of a styrene block as used herein. The “styrene isoprene block copolymer” refers to a polymer having at least one styrene block and at least one isoprene block (a segment having isoprene as a main monomer). Typical examples of styrene isoprene block copolymers are triblock copolymer (triblock body) having styrene blocks (hard segment) at both ends of isoprene block (soft segment), one isoprene block and one styrene. Examples thereof include a diblock copolymer (diblock body) composed of blocks. The “styrene butadiene block copolymer” refers to a polymer having at least one styrene block and at least one butadiene block (a segment containing butadiene as a main monomer).

  As the styrene block copolymer in the technique disclosed herein, for example, an embodiment in which the base polymer includes at least one of a styrene isoprene block copolymer and a styrene butadiene block copolymer is preferable. Of the styrene block copolymer contained in the pressure-sensitive adhesive, the proportion of the styrene isoprene block copolymer is 70% by mass or more, the proportion of the styrene butadiene block copolymer is 70% by mass or more, or styrene. The total ratio of the isoprene block copolymer and the styrene butadiene block copolymer is preferably 70% by mass or more. In a preferred embodiment, substantially all (for example, 95 to 100% by mass) of the styrenic block copolymer is a styrene isoprene block copolymer. In another preferred embodiment, substantially all (for example, 95 to 100% by mass) of the styrenic block copolymer is a styrene butadiene block copolymer. According to such a composition, the effect of applying the technique disclosed here can be better exhibited.

  The styrenic block copolymer may be in the form of a diblock body, a triblock body, a radial body, a mixture thereof, and the like. In a triblock body and a radial body, it is preferable that the styrene block is arranged at the terminal of the polymer chain. This is because the styrene blocks arranged at the end of the polymer chain are likely to gather to form a styrene domain, thereby forming a pseudo cross-linked structure and improving the cohesiveness of the pressure-sensitive adhesive. The styrenic block copolymer used in the technology disclosed herein has a diblock ratio of 30% by mass or more (more preferably 40% by mass or more, and still more preferably 50%) from the viewpoint of peel strength with respect to the adherend. % By mass or more, particularly preferably 60% by mass or more, and typically 65% by mass or more). A styrene block copolymer having a diblock ratio of 70% by mass or more (for example, 75% by mass or more) may be used. From the viewpoint of cohesion and the like, a styrene block copolymer having a diblock body ratio of 90% by mass or less (more preferably 85% by mass or less, for example, 80% by mass or less) can be preferably used. From the viewpoint of balancing a plurality of adhesive properties (peel strength, holding power, etc.) in a well-balanced manner by applying the technology disclosed herein, a styrene block copolymer having a diblock ratio of 60 to 85% by mass is preferable. A 70-85 mass% (for example, 70-80 mass%) styrene-type block copolymer is more preferable.

  The ratio of the diblock body to the styrene block copolymer (hereinafter sometimes referred to as “diblock body ratio” or “diblock ratio”) is determined by the following method. That is, a styrenic block copolymer is dissolved in tetrahydrofuran (THF), and GS5000H and G4000H liquid chromatographic columns manufactured by Tosoh Corporation are connected in series, each of which has a total of 4 stages, and THF is used as a mobile phase. High performance liquid chromatography is performed under conditions of a temperature of 40 ° C. and a flow rate of 1 mL / min. The peak area corresponding to the diblock body is measured from the obtained chart. And the diblock body ratio is calculated | required by calculating the percentage of the peak area corresponding to the said diblock body with respect to the whole peak area.

  The styrene content of the styrenic block copolymer may be, for example, 5 to 40% by mass. From the viewpoint of cohesiveness, a styrene block copolymer having a styrene content of 10% by mass or more (more preferably more than 10% by mass, for example, 12% by mass or more) is preferable. From the viewpoint of peel strength, the styrene content is preferably 35% by mass or less (typically 30% by mass or less, more preferably 25% by mass or less), and 20% by mass or less (typically less than 20% by mass). For example, 18% by mass or less) is particularly preferable. From the viewpoint of better exerting the effect of applying the technology disclosed herein (for example, the effect of improving the peel strength and holding force), the styrene block having a styrene content of 12% by mass or more and less than 20% by mass is used. A polymer can be preferably employed. The “styrene content” of the styrenic block copolymer refers to the mass ratio of the styrene component to the total mass of the block copolymer. The styrene content can be measured by NMR (nuclear magnetic resonance spectroscopy).

<Tackifying resin>
The pressure-sensitive adhesive disclosed herein preferably contains a tackifier resin in addition to the base polymer. The tackifying resin is selected from various known tackifying resins such as petroleum resins, styrene resins, coumarone / indene resins, terpene resins, modified terpene resins, rosin resins, rosin derivative resins, and ketone resins. Species or two or more can be used.

  Examples of petroleum resins include aliphatic (C5) petroleum resins, aromatic (C9) petroleum resins, aliphatic / aromatic copolymer (C5 / C9) petroleum resins, and hydrogenated products thereof ( Examples thereof include alicyclic petroleum resins obtained by hydrogenating aromatic petroleum resins.

  Examples of the styrenic resin include those based on a homopolymer of styrene, those based on an α-methylstyrene homopolymer, those based on a vinyltoluene homopolymer, styrene, A main component of a copolymer containing two or more of α-methylstyrene and vinyltoluene in the monomer composition (for example, an α-methylstyrene / styrene copolymer having an α-methylstyrene / styrene copolymer as a main component) Polymer resin) and the like.

  As the coumarone-indene resin, a resin containing coumarone and indene as a monomer component constituting the resin skeleton (main chain) can be used. Examples of monomer components that can be contained in the resin skeleton other than coumarone and indene include styrene, α-methylstyrene, methylindene, and vinyltoluene.

  Examples of terpene resins include α-pinene polymers, β-pinene polymers, dipentene polymers, and the like. Examples of the modified terpene resin include those obtained by modifying the terpene resin (phenol modification, styrene modification, hydrogenation modification, hydrocarbon modification, etc.). Specific examples include terpene phenol resins, styrene-modified terpene resins, hydrogenated terpene resins, and the like.

  The above-mentioned “terpene phenol resin” refers to a polymer containing a terpene residue and a phenol residue, a copolymer of a terpene and a phenol compound (terpene-phenol copolymer resin), and a terpene homopolymer or copolymer. It is a concept that includes both a combination (terpene resin, typically unmodified terpene resin) and phenol-modified (phenol-modified terpene resin). Preferable examples of the terpene constituting the terpene phenol resin include monoterpenes such as α-pinene, β-pinene and limonene (including d-form, l-form and d / l-form (dipentene)).

  Specific examples of the rosin resin include unmodified rosins such as gum rosin, wood rosin and tall oil rosin (raw rosin); modified rosins modified by hydrogenation, disproportionation, polymerization, etc. (hydrogenation) Rosin, disproportionated rosin, polymerized rosin, and other chemically modified rosins). Examples of rosin derivative resins include those obtained by esterifying unmodified rosin with alcohols (that is, rosin esterified products) and modified rosins (hydrogenated rosin, disproportionated rosin, polymerized rosin, etc.) with alcohols. Rosin esters such as esterified products (ie, esterified products of modified rosin); Unmodified rosin or modified rosin (hydrogenated rosin, disproportionated rosin, polymerized rosin, etc.) modified with unsaturated fatty acid Rosins; Unsaturated fatty acid-modified rosin esters obtained by modifying rosin esters with unsaturated fatty acids; Unmodified rosin, modified rosin (hydrogenated rosin, disproportionated rosin, polymerized rosin, etc.), unsaturated fatty acid-modified rosin or Rosin alcohols with reduced carboxyl groups in saturated fatty acid-modified rosin esters; unmodified rosin, modified Metal salts of rosins (particularly rosin esters) such as gin and various rosin derivatives; obtained by adding phenol to an rosin (unmodified rosin, modified rosin, various rosin derivatives, etc.) with an acid catalyst and thermal polymerization. Rosin phenol resin; and the like.

<High softening point resin>
Adhesives disclosed herein, as the tackifying resin, a softening point preferably contains 120 ° C. or more tackifying resin (high softening point resin) T _H. From the viewpoint of aggregation property, the softening point of the high softening point resin _{T H} is preferably at least 125 ° C., more preferably at least 130 ° C., more preferably 135 ° C. or higher (e.g., 140 ° C. or higher). Further, from the viewpoint of peel strength to the adherend, the softening point of the high softening point resin T _H is suitably about 200 ° C. or less, preferably 180 ° C. or less, more preferably 170 ° C. or less (e.g., 160 ° C. or less ).

  The softening point of the tackifying resin disclosed herein is defined as a value measured based on the softening point test method (ring ball method) defined in JIS K5902 and JIS K2207. Specifically, the sample is melted as quickly as possible, and is carefully filled so that no bubbles are formed in the ring placed on a flat metal plate. After cooling, cut off the raised part from the plane including the top of the ring with a slightly heated sword. Next, a supporter (ring stand) is put in a glass container (heating bath) having a diameter of 85 mm or more and a height of 127 mm or more, and glycerin is poured until the depth becomes 90 mm or more. Next, the steel ball (diameter 9.5 mm, weight 3.5 g) and the ring filled with the sample are immersed in glycerin so as not to contact each other, and the temperature of glycerin is maintained at 20 ° C. plus or minus 5 ° C. for 15 minutes. . Next, a steel ball is placed on the center of the surface of the sample in the ring, and this is placed in a fixed position on the support. Next, the distance from the upper end of the ring to the glycerin surface is maintained at 50 mm, a thermometer is placed, the center of the mercury bulb of the thermometer is set to the same height as the center of the ring, and the container is heated. The flame of the Bunsen burner used for heating is placed between the center and the edge of the bottom of the container so that the heating is even. It should be noted that the rate at which the bath temperature rises after reaching 40 ° C. after heating has started must be 5.0 plus or minus 0.5 ° C. per minute. The temperature at the time when the sample gradually softens and flows down from the ring and finally comes into contact with the bottom plate is read and used as the softening point. Two or more softening points are measured simultaneously, and the average value is adopted.

Adhesives disclosed herein as a high softening point resin T _H, for example, can be used terpene phenol resins, rosin phenolic resins, polymerized rosin, the esterified products of polymerized rosin. Such high softening point resins can be used singly or in combination of two or more. As a preferred embodiment, it includes embodiments comprising one or more terpene phenol resin as a high-softening point resin T _H. A terpene phenol resin having a softening point of 120 ° C. or higher and 200 ° C. or lower (typically 120 ° C. or higher and 180 ° C. or lower, eg, 125 ° C. or higher and 170 ° C. or lower) can be preferably used. If the softening point is too low, the holding force may tend to decrease. If the softening point is too high, the peel strength with respect to the adherend may tend to decrease.

Although not particularly limited, as a preferred embodiment, for example, more than 25 wt% of a high softening point resin T _H (more preferably at least 30 wt%) can be cited aspects a terpene phenol resin. Least 50 wt% of a high softening point resin T _H (more preferably 70 mass% or more, more preferably 80 mass% or more, for example 90 wt% or more) may be a terpene phenol resin, high softening point resin T _H Substantially all (for example, 95% by mass or more) may be a terpene phenol resin.

Art disclosed herein, for example, as a high softening point resin _{T H,} preferably carried out in a manner that includes a tackifier resin (a high softening point _{resin) T H1} having a hydroxyl value of 80 mg KOH / g or more (e.g. 90 mgKOH / g or higher) Can be done. The hydroxyl value of the high softening point resin _{T H1} is typically less 200 mg KOH / g, preferably 180 mg KOH / g or less (e.g., 160 mgKOH / g or less). According to the pressure-sensitive adhesive containing the high softening point resin _TH1 , a higher-performance pressure-sensitive adhesive sheet can be realized. A pressure-sensitive adhesive sheet that achieves a higher level of cohesion (for example, high-temperature cohesion) and other properties (for example, peel strength) can be realized. In the art disclosed herein, high softening point resin T _H1 includes a block copolymer of is more preferably used in combination with the rubber-based polymer as the base polymer, monovinyl-substituted aromatic compound and a conjugated diene compound It is particularly preferred to use in combination with a base polymer.

Here, as the value of “hydroxyl value” in this specification, a value measured by a potentiometric titration method defined in JIS K0070: 1992 can be adopted. The specific measurement method is as follows.
[Measurement method of hydroxyl value]
1. Reagent (1) As an acetylating reagent, about 12.5 g (about 11.8 mL) of acetic anhydride is taken, and pyridine is added thereto to make a total volume of 50 mL, and the mixture is sufficiently stirred. Alternatively, about 25 g (about 23.5 mL) of acetic anhydride is taken, and pyridine is added thereto to make a total volume of 100 mL, and the mixture is sufficiently stirred.
(2) As a measuring reagent, a 0.5 mol / L potassium hydroxide ethanol solution is used.
(3) Prepare toluene, pyridine, ethanol and distilled water.
2. Operation (1) About 2 g of a sample is accurately weighed in a flat bottom flask, 5 mL of an acetylating reagent and 10 mL of pyridine are added, and an air cooling tube is attached.
(2) The flask was heated in a bath at 100 ° C. for 70 minutes, allowed to cool, and 35 mL of toluene was added as a solvent from the top of the condenser and stirred, and then 1 mL of distilled water was added and stirred to acetic anhydride. Disassemble. Heat again in the bath for 10 minutes to complete decomposition and allow to cool.
(3) Wash the cooling tube with 5 mL of ethanol and remove it. Next, 50 mL of pyridine is added as a solvent and stirred.
(4) Add 25 mL of 0.5 mol / L potassium hydroxide ethanol solution using a whole pipette.
(5) Potentiometric titration with 0.5 mol / L potassium hydroxide ethanol solution. The inflection point of the obtained titration curve is the end point.
(6) In the blank test, the above (1) to (5) are performed without putting a sample.
3. Calculation The hydroxyl value is calculated by the following formula.
Hydroxyl value (mgKOH / g) = [(BC) × f × 28.05] / S + D
here,
B: Amount of 0.5 mol / L potassium hydroxide ethanol solution used for the blank test (mL),
C: The amount of 0.5 mol / L potassium hydroxide ethanol solution used for the sample (mL),
f: factor of 0.5 mol / L potassium hydroxide ethanol solution,
S: Mass of sample (g),
D: Acid value,
28.05: 1/2 of the molecular weight of potassium hydroxide 56.11,
It is.

The high softening point resin T _H1, those having a predetermined value or more hydroxyl number of high softening point resin T _H of the various described above, can be used in combination singly or in combination of two or more thereof as appropriate . In a preferred embodiment, at least a terpene phenol resin is used as the high softening point resin _TH1 . The terpene phenol resin is preferable because the hydroxyl value can be arbitrarily controlled by the copolymerization ratio of phenol. 50 wt% or more of the high softening point resin _{T H1} (more preferably 70 mass% or more, for example 90 or more mass%) is preferably is a terpene phenol resin, substantially all (e.g. 95 to 100 wt%, further May be terpene phenol resin.

Adhesives disclosed herein as a high softening point resin _{T H,} a hydroxyl value of 0 or 80 mg KOH / g of less than tackifier resin (high softening point _resin) may contain a _{T H2.} The high softening point resin T _H2, may be used in place of the high softening point resin T _H1, it may be used in combination with a high softening point resin T _H1. As a preferred embodiment, the hydroxyl value is between 80 mg KOH / g or more high softening point resin _{T H1,} it includes embodiments comprising a high softening point resin _{T H2.} Among them, the above-described rubber-based polymer as a base polymer, a block copolymerization with it is more preferable to use a combination of a high softening point resin T _H1 and T _H2, monovinyl-substituted aromatic compound as the base polymer and a conjugated diene compound It is particularly preferable to use the combination and the high softening point resins _TH1 and _TH2 in combination. The high softening point resin T _H2, those hydroxyl value of the high softening point resin T _H of the various described above is in the above range, it can be used in combination singly or in combination of two or more thereof as appropriate. For example, terpene phenol resins having a hydroxyl value of 0 or more and less than 80 mgKOH / g, petroleum resins (for example, C5 petroleum resins), terpene resins (for example, β-pinene polymer), rosin resins (for example, polymerized rosin), rosin A derivative resin (for example, esterified product of polymerized rosin) or the like can be used.

The art disclosed herein, the PSA is a hydroxyl value 80 mg KOH / g or more (typically 80~160mgKOH / g, for example 80~140mgKOH / g) and a high softening point resin _{T H1} of a hydroxyl value 0 mgKOH / g or 80 mg KOH / less g (typically 40 mg KOH / g or higher 80 mg KOH / less g) may be preferably carried out in a manner that includes a combination of a high softening point resin _{T H2} of. In this case, the relationship between the amounts used of T _H1 and T _H2 can be set so that, for example, the mass ratio (T _H1 : T _H2 ) is in the range of 1: 5 to 5: 1. It is appropriate to set it in the range of 3 to 3: 1 (for example, 1: 2 to 2: 1). A preferred embodiment is an embodiment in which T _H1 and T _H2 are both terpene phenol resins.

Adhesives disclosed herein, depending on the purpose, application, and the like, as a high softening point resin T _H, the tackifying resin has an aromatic ring and a hydroxyl value of at most 30 mgKOH / g (high softening point resin) T _It may contain _HR1 . This can effectively improve the cohesiveness (for example, high temperature cohesiveness). In addition, the use of the tackifying resin _THR1 is particularly effective for improving the adhesion to the polishing pad (typically improving the shear adhesion) and the temperature for the adhesion to the polishing pad (typically 180 degree peel strength). It is also preferable in terms of reducing dependency. Tackifying resin _THR1 can be used individually by 1 type or in combination of 2 or more types. The hydroxyl value of the tackifier resin _{T HR1} is preferably less than 10 mgKOH / g, more preferably less than 5 mgKOH / g, more preferably less than 3 mgKOH / g. For example, hydroxyl value or is less than 1 mgKOH / g, or hydroxyl group may be used preferably a tackifier resin _{T HR1} undetected.

Examples of tackifying resins having an aromatic ring include the above-described aromatic petroleum resins, aliphatic / aromatic copolymer petroleum resins, styrene resins, coumarone-indene resins, styrene-modified terpene resins, phenol-modified terpene resins, A rosin phenol resin etc. are mentioned. Among these, those having a softening point of 120 ° C. or higher (preferably 130 ° C. or higher, eg 135 ° C. or higher) and a hydroxyl value of 30 mgKOH / g or lower (preferably less than 5 mgKOH / g, eg less than 1 mgKOH / g) It can be employed as _THR1 .

Preferable examples of materials that can be used as the tackifying resin _THR1 include aromatic petroleum resins, aliphatic / aromatic copolymer petroleum resins, styrene resins, and coumarone-indene resins. As the aliphatic / aromatic copolymer petroleum resin, the copolymerization ratio of the C5 fraction is less than 15% by mass (more preferably less than 10% by mass, even more preferably less than 5% by mass, for example, less than 3% by mass). Is preferred. Moreover, the copolymerization ratio of C9 fraction is 55% by mass or more (more preferably 60% by mass or more, and further preferably 65% by mass or more). Particularly preferred tackifying resins _THR1 include aromatic petroleum resins and styrene resins (for example, α-methylstyrene / styrene copolymer resins).

The usage-amount of tackifying resin _THR1 is not restrict _| limited in particular, According to the objective and use of an adhesive, it can set suitably. From the viewpoint of aggregating property (for example, high temperature aggregating property), the amount of the tackifying resin _THR1 used relative to 100 parts by mass of the base polymer is preferably 5 parts by mass or more, and more preferably 10 parts by mass or more. Moreover, from the viewpoint of making cohesiveness (for example, high temperature cohesiveness) and peel strength compatible at a high level, the amount of the tackifier resin _THR1 used relative to 100 parts by mass of the base polymer can be, for example, 100 parts by mass or less. 80 mass parts or less (for example, 60 mass parts or less) is preferable. Considering the adhesive performance (for example, peel strength) at low temperature, the amount of the tackifier resin _THR1 used relative to 100 parts by mass of the base polymer is preferably 40 parts by mass or less, and more preferably 30 parts by mass or less (for example, 25 parts by mass or less). .

Although it does not specifically limit, In the aspect whose base polymer is a styrene-type block copolymer, the usage-amount of tackifying resin _{THR1 with} respect to 1 mass part of styrene components in this block copolymer is 0.1 mass, for example In terms of cohesiveness (for example, high temperature cohesiveness), 0.2 part by mass or more is preferable, and 0.5 part by mass or more is more preferable. Moreover, the usage-amount of tackifying resin _{THR1 with} respect to 1 mass part of styrene components in a block copolymer can be made into 10 mass parts or less, for example, and a cohesiveness (for example, high temperature cohesiveness) and peeling strength are a high level. Is preferably 7 parts by mass or less, more preferably 5 parts by mass or less.

In another preferable embodiment of the pressure-sensitive adhesive disclosed herein, the high softening point resin _TH has an aromatic ring and is substantially free of isoprene units, terpene skeleton and rosin skeleton (high softening point). Resin) may contain _THR2 . This effectively improves the cohesive force (for example, high-temperature cohesive force). In addition, the use of the above-mentioned tackifying resin _THR2 is particularly effective for improving the adhesiveness to the polishing pad (typically improving the shear adhesive strength) and the adhesive strength to the polishing pad (typically 180 degree peel strength). It is also preferable in terms of reducing dependency. Tackifying resin _THR2 can be used individually by 1 type or in combination of 2 or more types. Here, the tackifying resin _THR2 substantially does not contain an isoprene unit, a terpene skeleton, and a rosin skeleton. The proportion of these structural parts (that is, the isoprene unit, the terpene skeleton, and the rosin skeleton) in the tackifying resin _THR2. Is less than 10% by mass in total (more preferably less than 8% by mass, even more preferably less than 5% by mass, for example, less than 3% by mass). The said ratio may be 0 mass%. In addition, the ratio of the isoprene unit, the terpene skeleton, and the rosin skeleton in the tackifying resin _THR2 can be measured by, for example, NMR (nuclear ceramic resonance spectrum method).

Examples of tackifying resins having an aromatic ring and substantially free of isoprene units, terpene skeletons and rosin skeletons include the above-mentioned aromatic petroleum resins, aliphatic / aromatic copolymer petroleum resins, and styrene resins. And coumarone-indene resin. Among these, those having a softening point of 120 ° C. or higher (preferably 130 ° C. or higher, eg, 135 ° C. or higher) can be adopted as the tackifying resin _THR2 . Particularly preferred tackifying resins _THR2 include aromatic petroleum resins and styrene resins (for example, α-methylstyrene / styrene copolymer resins).

The amount of the tackifying resin _THR2 used is not particularly limited, and can be appropriately set according to the purpose and application of the pressure-sensitive adhesive. From the viewpoint of aggregating property (for example, high temperature aggregating property), the amount of the tackifying resin _THR2 used relative to 100 parts by mass of the base polymer is preferably 5 parts by mass or more, and more preferably 10 parts by mass or more. Moreover, from the viewpoint of making cohesiveness (for example, high temperature cohesiveness) and peel strength compatible at a high level, the amount of the tackifier resin _THR2 used relative to 100 parts by mass of the base polymer can be, for example, 100 parts by mass or less. 80 mass parts or less (for example, 60 mass parts or less) is preferable. From the viewpoint of adhesive performance (for example, peel strength) at low temperature, the amount of the tackifier resin _THR2 used relative to 100 parts by mass of the base polymer is preferably 40 parts by mass or less, more preferably 30 parts by mass or less (for example, 25 parts by mass or less). preferable.

Although it does not specifically limit, In the aspect whose base polymer is a styrene block copolymer, the usage-amount of tackifying resin _{THR2 with} respect to 1 mass part of styrene components in this block copolymer is 0.1 mass, for example In terms of cohesiveness (for example, high temperature cohesiveness), 0.2 part by mass or more is preferable, and 0.5 part by mass or more is more preferable. Moreover, the usage-amount of tackifying resin _{THR2 with} respect to 1 mass part of styrene components in a block copolymer can be made into 10 mass parts or less, for example, and a cohesiveness (for example, high temperature cohesiveness) and peeling strength are a high level. Is preferably 7 parts by mass or less, more preferably 5 parts by mass or less.

Although not particularly limited, as the tackifier resin _{T HR2,} for the same reason as the tackifier resin _{T HR1,} hydroxyl value 30 mgKOH / g or less (preferably less than 5 mgKOH / g, for example less than 1 mgKOH / g) of those Can be preferably employed. Therefore, as the tackifying resin _THR2 in the technology disclosed herein, those corresponding to the tackifying resin _THR1 can be preferably used. Similarly, as tackifying resin _THR1 in the technique disclosed here, what corresponds also to tackifying resin _THR2 can be used preferably.

Adhesives disclosed herein may include a terpene phenol resin as a high-softening point resin T _H, the high softening point resin T _H total 25% by mass or more (more preferably at least 30 wt%) is a terpene phenolic resin It is preferable. Least 50 wt% of a high softening point resin T _H (more preferably 70 mass% or more, more preferably 80 mass% or more, for example 90 wt% or more) may be a terpene phenol resin, high softening point resin T _H Substantially all (for example, 95% by mass or more) may be a terpene phenol resin. For example, substantially all of the high softening point resin T _H can be a terpene phenol resin A and the terpene phenol resin B will be described later.

Adhesives disclosed herein, when a high softening point resin T _H terpene phenol resin, a terpene phenol resin 20 parts by mass or more with respect to 100 parts by mass of the base polymer (preferably 35 parts by mass or more, for example 40 weight Part or more). Usually, it is appropriate that the content of the terpene phenol resin is 100 parts by mass or less (preferably 80 parts by mass or less, for example 70 parts by mass or less).

In the art disclosed herein, when using a high softening point resin T _H, is not particularly limited, high softening point total of the resin T _H (i.e., softening point 120 ° C. or more adhesive to the base polymer 100 parts by weight From the viewpoint of cohesiveness (for example, high-temperature cohesiveness) and the like, the total amount of the imparting resin can be, for example, 10 parts by mass or more, preferably 20 parts by mass or more (preferably 25 parts by mass or more, for example, 35 parts by mass or more, typically Specifically, 40 parts by mass or more) is preferable. Further, from the viewpoint of peel strength and low temperature properties (e.g., low temperature peel strength), the content of the high softening point resin T _H for 100 parts by mass of the base polymer is usually suitably 120 parts by mass or less, preferably 100 parts by weight Below, more preferably 80 parts by mass or less (for example, 70 parts by mass or less, typically 60 parts by mass or less). By the amount of high softening point resin T _H for 100 parts by mass of the base polymer and 55 parts by mass or less (for example, 50 parts by mass or less), higher peel strength can be achieved.

The proportion of high softening point resin T _H of the total tackifying resin which may be contained in the adhesive disclosed herein is not particularly limited. The said ratio can be 30-90 mass%, for example, and 50-80 mass% is preferable. Incidentally, the art disclosed herein may be embodied with the PSA contains no high softening point resin T _H.

<Low softening point resin T _L >
As a suitable example of the aspect containing other tackifying resin, the aspect containing tackifying resin (low softening point resin) _TL with a softening point of less than 120 degreeC is mentioned. According to such an embodiment, for example, a pressure-sensitive adhesive sheet with better peel strength can be realized. The lower limit of the softening point of the low softening point resin _TL is not particularly limited. Those having a softening point of 40 ° C. or higher (typically 60 ° C. or higher) can be preferably used. A low softening point resin _TL having a softening point of 80 ° C. or higher (more preferably 100 ° C. or higher) and lower than 120 ° C. can be preferably employed from the viewpoint of achieving both high cohesiveness and peel strength. Especially, use of low softening point resin _TL whose softening point is 110 degreeC or more and less than 120 degreeC is preferable. The low softening point resin T _L, it is particularly preferable to use in combination with the high softening point resin T _H above. Further, the low softening point resin _TL is more preferably used in combination with the rubber-based polymer as a base polymer, and is used in combination with a block copolymer of a monovinyl-substituted aromatic compound and a conjugated diene compound as the base polymer. It is particularly preferred.

The hydroxyl value and structure of the low softening point resin _TL (for example, the presence or absence of an aromatic ring, the presence or absence of an isoprene unit, the presence or absence of a terpene skeleton, the presence or absence of a rosin skeleton) are not particularly limited. Various tackifying resins (petroleum resin, styrene resin, coumarone / indene resin, terpene resin, modified terpene resin, rosin resin, rosin derivative resin, ketone resin, etc.) having a softening point of less than 120 ° C. Those can be appropriately selected and used.

The technique disclosed here can be preferably implemented in a mode in which the pressure-sensitive adhesive contains at least one of a petroleum resin and a terpene resin as the low softening point resin _TL . For example, a composition in which the main component of the low softening point resin _TL (that is, a component occupying more than 50% by mass of the low softening point resin _TL ) is a petroleum resin, a composition that is a terpene resin, a petroleum resin and a terpene resin A composition that is a combination of the above and the like can be preferably employed. From the viewpoint of peel strength and compatibility, an embodiment in which the main component of the low softening point resin _TL is a terpene resin (for example, β-pinene polymer) is preferable. A terpene resin may be sufficient as substantially all (for example, 95 mass% or more) of low softening point resin _TL .

When the adhesive as disclosed herein comprises a low softening point resin T _L, the total amount of low softening point resin T _L for 100 parts by mass of the base polymer is not particularly limited, it can be, for example, 10 parts by mass or more, peeling From the viewpoint of strength, 15 parts by mass or more is preferable, and 20 parts by mass or more is more preferable. The total amount of the low softening point resin _TL with respect to 100 parts by mass of the base polymer is suitably 120 parts by mass or less, preferably 90 parts by mass or less, and 70 parts by mass or less (for example, 60 parts by mass or less) from the viewpoint of cohesiveness. ) Is more preferable. The content of the low softening point resin _TL may be 50 parts by mass or less (for example, 40 parts by mass or less).

When the adhesive as disclosed herein includes a low softening point resin T _L and a high softening point resin T _H, the relationship between their usage, T _L: Mass ratio of T _H 1: 5 to 3: 1 It is preferable to set so as to be (more preferably 1: 5 to 2: 1). The art disclosed herein, the embodiments the adhesive is rich in _{T H} than _{T L} as the tackifier resin _(e.g., T L: Mass ratio of _{T H} 1: 1.2 to 1: 5) It can be preferably implemented. According to this aspect, a higher performance pressure-sensitive adhesive sheet can be realized.

The proportion of the low softening point resin _{TL in} the total tackifying resin that can be included in the pressure-sensitive adhesive disclosed herein is not particularly limited. The said ratio can be 10-70 mass%, for example, and 20-50 mass% is preferable. In addition, you may implement the technique disclosed here in the aspect which does not contain low softening point resin _TL .

<Combination of terpene phenol resins having different hydroxyl values>
The pressure-sensitive adhesive disclosed herein is a form containing a base polymer composed of a block copolymer of a monovinyl-substituted aromatic compound and a conjugated diene compound, and a tackifier resin, and the terpene phenol resin A is used as the tackifier resin. And terpene phenol resin B at least. Here, the terpene phenol resin A and the terpene phenol resin B have a hydroxyl value A _OH (mg KOH / g) of the terpene phenol resin A and a hydroxyl value B _OH (mg KOH / g) of the terpene phenol resin B of A _OH > B _OH It is preferable to select so as to satisfy the relationship. By using the terpene phenol resins A and B in combination, for example, the peel strength (particularly, peel strength after time) of the pressure-sensitive adhesive sheet can be improved.

Typically, the difference between the hydroxyl value _{A OH} and hydroxyl value _{B OH,} i.e. _A OH _{-B OH} is such that the larger 200 mg KOH / g or less than 0, it is appropriate to select a terpene phenol resin A, B . In a preferred embodiment, A _OH -B _OH is 5 to 150 mg KOH / g (typically 10 to 120 mg KOH / g, more preferably 15 to 100 mg KOH / g, such as 20 to 80 mg KOH / g or less).

The hydroxyl value of each of the terpene phenol resins A and B is not particularly limited. For _{example, A OH} and _{B OH} are both 80 mg KOH / g or more (typically 80~250mgKOH / g, preferably 80~220mgKOH / g, for example 90~160mgKOH / g) may _{be, A OH} and B _OH is less than both 80 mg KOH / g (typically less than 0 or 80 mg KOH / g, preferably less than 10 mgKOH / g or higher 80 mg KOH / g, for example 20~70mgKOH / g) may _{be, a OH} is 80 mg KOH / g not less _{than, B OH} is may be less than 80 mg KOH / g. In a preferred embodiment, A _OH is 80 mg KOH / g or more (typically 80 to 160 mg KOH / g, preferably 80 to 140 mg KOH / g, such as 90 to 120 mg KOH / g), and B _OH is less than 80 mg KOH / g (typical thereof include 0 to less than 80 mg KOH / g, preferably less than 10 mgKOH / g or higher 80 mg KOH / g, for example 20~70mgKOH / g) and is, and _a OH _{-B OH} is 10 mgKOH / g or more (preferably 20 mgKOH / g or more, For example, it is 30 mgKOH / g or more, and typically 100 mgKOH / g or less).

  Each content of terpene phenol resin A and B can be 1 mass part or more with respect to 100 mass parts of base polymers, respectively. In order to better demonstrate the effect of using the terpene phenol resin A and the terpene phenol resin B in combination, the content of the terpene phenol resins A and B with respect to 100 parts by mass of the base polymer is 5 parts by mass or more ( It is preferably 10 parts by mass or more, for example, 15 parts by mass or more. In addition, from the viewpoint of peel strength with respect to the adherend (particularly peel strength at low temperature), the total content of the terpene phenol resins A and B is usually 100 parts by mass or less with respect to 100 parts by mass of the base polymer. Is preferably 90 parts by mass or less, more preferably 80 parts by mass or less (for example, 70 parts by mass or less). For example, an embodiment in which the total content of the terpene phenol resins A and B with respect to 100 parts by mass of the base polymer is 15 to 80 parts by mass (typically 25 to 60 parts by mass) can be preferably adopted.

The mass ratio (m _A : m _B ) between the content m _A of the terpene phenol resin _A and the content m _B of the terpene phenol resin B can be, for example, 1:10 to 10: 1. From the viewpoint of the balance between the peel strength to the adherend and the constant load peel characteristics (particularly the constant load peel characteristics under wet heat conditions), the mass ratio (m _A : m _B ) is usually set to 1: 5. 5: 1 is appropriate, for example, 1: 3 to 3: 1. In a preferred embodiment, the mass ratio _m A / _{m B} is 0.7 to 10 (more preferably 0.8 to 5, typically 0.9 to 4, e.g., 1 to 3) and so as to _m A, m _B can be set. According to such an embodiment, a pressure-sensitive adhesive sheet having excellent resistance to continuous stress and excellent temporal stability of adhesive performance (for example, peel strength) can be realized.

  The softening points of the terpene phenol resins A and B are not particularly limited. For example, the softening points of the terpene phenol resins A and B are both 120 ° C. or higher (typically higher than 120 ° C., preferably 125 ° C. or higher, such as 130 ° C. or higher, typically 180 ° C. or lower). Both may be less than 120 ° C. Moreover, the softening point of any one of terpene phenol resin A and B may be 120 degreeC or more, and the other softening point may be less than 120 degreeC. In a preferred embodiment, the terpene phenol resins A and B each have a softening point in the range of 120 ° C to 170 ° C. For example, terpene phenol resin A having a softening point of 120 ° C to 170 ° C and a hydroxyl value of 80 to 140 mgKOH / g, and a softening point of 120 ° C to 170 ° C and a hydroxyl value of less than 80 mgKOH / g (for example, 20 A combination with terpene phenol resin B which is ˜70 mg KOH / g) can be preferably employed.

  In addition, the adhesive disclosed here may further contain terpene phenol resins other than the terpene phenol resin A and the terpene phenol resin B as the tackifier resin. When the pressure-sensitive adhesive contains three or more types of terpene phenol resins, two types are selected from the terpene phenol resins in descending order of mass-based content, and the higher hydroxyl value is selected from the terpene phenols. The resin A and the lower hydroxyl value are referred to as terpene phenol resin B. In addition, for example, as the terpene phenol resin having the highest content on a mass basis, when three types of terpene phenol resins are included at a mass ratio of approximately 1: 1: 1, the one having the highest hydroxyl value is selected. The terpene phenol resin A is used, and the terpene phenol resin B is the one having the lowest hydroxyl value.

  When using the tackifying resin in the technology disclosed herein, the total amount of the tackifying resin with respect to 100 parts by mass of the base polymer is not particularly limited, but is usually 20 parts by mass from the viewpoint of realizing a good balance between cohesiveness and peel strength. The above is appropriate, preferably 30 parts by mass or more, and more preferably 40 parts by mass or more (for example, 50 parts by mass or more). In addition, from the viewpoint of low temperature characteristics (for example, low temperature peel strength), the content of the tackifier resin with respect to 100 parts by mass of the base polymer is usually suitably 200 parts by mass or less, preferably 150 parts by mass or less, and 120 parts by mass. The following (for example, 100 parts by mass or less) is more preferable.

<Isocyanate compound>
The pressure-sensitive adhesive composition used for forming the pressure-sensitive adhesive (pressure-sensitive adhesive layer) disclosed herein may contain an isocyanate compound. According to such a pressure-sensitive adhesive composition, a higher-performance pressure-sensitive adhesive sheet (for example, excellent in repulsion resistance and constant load peeling characteristics) can be realized. As the isocyanate compound, polyfunctional isocyanate (refers to a compound having an average of two or more isocyanate groups per molecule, including those having an isocyanurate structure) can be preferably used. As this polyfunctional isocyanate, 1 type (s) or 2 or more types selected from the various isocyanate compounds (polyisocyanate) which have a 2 or more isocyanate group in 1 molecule can be used. Examples of such polyfunctional isocyanates include aliphatic polyisocyanates, alicyclic polyisocyanates, aromatic polyisocyanates and the like.

  Specific examples of the aliphatic polyisocyanates include 1,2-ethylene diisocyanate; tetramethylene diisocyanate such as 1,2-tetramethylene diisocyanate, 1,3-tetramethylene diisocyanate, 1,4-tetramethylene diisocyanate; -Hexamethylene diisocyanate such as hexamethylene diisocyanate, 1,3-hexamethylene diisocyanate, 1,4-hexamethylene diisocyanate, 1,5-hexamethylene diisocyanate, 1,6-hexamethylene diisocyanate, 2,5-hexamethylene diisocyanate; Examples include 2-methyl-1,5-pentane diisocyanate, 3-methyl-1,5-pentane diisocyanate, and lysine diisocyanate.

  Specific examples of alicyclic polyisocyanates include isophorone diisocyanate; cyclohexyl diisocyanates such as 1,2-cyclohexyl diisocyanate, 1,3-cyclohexyl diisocyanate, 1,4-cyclohexyl diisocyanate; 1,2-cyclopentyl diisocyanate, 1,3 -Cyclopentyl diisocyanate such as cyclopentyl diisocyanate; hydrogenated xylylene diisocyanate, hydrogenated tolylene diisocyanate, hydrogenated diphenylmethane diisocyanate, hydrogenated tetramethylxylene diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, and the like.

  Specific examples of the aromatic polyisocyanates include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4′-diphenylmethane diisocyanate, 2,4′-diphenylmethane diisocyanate, and 2,2′-diphenylmethane diisocyanate. 4,4′-diphenyl ether diisocyanate, 2-nitrodiphenyl-4,4′-diisocyanate, 2,2′-diphenylpropane-4,4′-diisocyanate, 3,3′-dimethyldiphenylmethane-4,4′-diisocyanate 4,4'-diphenylpropane diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, naphthylene-1,4-diisocyanate, naphthylene-1,5-diisocyanate, 3,3'-dimethoxy Diphenyl-4,4'-diisocyanate, xylylene-1,4-diisocyanate, xylylene-1,3-diisocyanate.

  Examples of preferred isocyanate compounds include polyfunctional isocyanates having an average of 3 or more isocyanate groups per molecule. Such a trifunctional or higher functional isocyanate is a difunctional or trifunctional or higher polymer (typically a dimer or trimer), a derivative (for example, a polyhydric alcohol and two or more polyfunctional isocyanates). Addition reaction product), polymer and the like. For example, diphenylmethane diisocyanate dimer or trimer, hexamethylene diisocyanate isocyanurate (trimer adduct of isocyanurate structure), reaction product of trimethylolpropane and tolylene diisocyanate, trimethylolpropane and hexamer Examples of the reaction product with methylene diisocyanate include polyfunctional isocyanates such as polymethylene polyphenyl isocyanate, polyether polyisocyanate, and polyester polyisocyanate. As commercial products of such polyfunctional isocyanates, trade names “Duranate TPA-100” manufactured by Asahi Kasei Chemicals, trade names “Coronate L”, “Coronate HL”, “Coronate HK” manufactured by Nippon Polyurethane Industry Co., Ltd. “Coronate HX”, “Coronate 2096” and the like.

  When using an isocyanate compound, the amount used is not particularly limited. For example, the amount is more than 0 parts by mass and 10 parts by mass or less (typically 0.01 to 10 parts by mass) with respect to 100 parts by mass of the base polymer. Can do. Usually, it is appropriate that the amount of the isocyanate compound used is 100 to 10 parts by mass with respect to 100 parts by mass of the base polymer, and 0.1 to 5 parts by mass (typically 0.3 to 3 parts by mass, For example, it is preferable to set it as 0.5-1 mass part. By using an isocyanate compound within such a range, a pressure-sensitive adhesive sheet having an excellent performance balance can be realized.

<Other ingredients>
The pressure-sensitive adhesive disclosed herein may be a leveling agent, a crosslinking agent, a crosslinking aid, a plasticizer, a softening agent, a filler, a colorant (pigment, dye, etc.), an antistatic agent, an anti-aging agent, if necessary. It may contain various additives that are common in the field of pressure-sensitive adhesives, such as ultraviolet absorbers, antioxidants, and light stabilizers. About such various additives, a conventionally well-known thing can be used by a conventional method. The pressure-sensitive adhesive disclosed herein contains substantially no liquid rubber such as polybutene (for example, the content per 100 parts by mass of the base polymer may be 1 part by mass or less, and may be 0 part by mass). The embodiment can be preferably implemented. According to the pressure-sensitive adhesive, a pressure-sensitive adhesive sheet having more excellent repulsion resistance and / or constant load peeling characteristics can be realized.

  In a preferred embodiment, the pressure-sensitive adhesive is such that the total amount of the base polymer and the tackifying resin is 90% by mass or more of the total mass of the pressure-sensitive adhesive (that is, the mass of the pressure-sensitive adhesive layer constituted by the pressure-sensitive adhesive). It can be an occupying composition. For example, an embodiment in which the total amount of the base polymer and the tackifier resin is 90 to 99.8% by mass (typically, for example, 95 to 99.5% by mass) of the total mass of the adhesive can be preferably adopted. .

  In another preferred embodiment, the pressure-sensitive adhesive composition may be a composition substantially free of a chelate compound. Here, the chelate compound is, for example, a chelate compound of an alkaline earth metal oxide and a resin (alkylphenol resin or the like) having a functional group (hydroxyl group, methylol group or the like) capable of coordinating the oxide. Point to. The technology disclosed herein can be preferably implemented in such a manner that the pressure-sensitive adhesive composition does not contain such a chelate compound at all or the content of the chelate compound is 1% by mass or less. According to such an embodiment, a pressure-sensitive adhesive sheet with more excellent adhesive strength can be realized.

  The form of the pressure-sensitive adhesive composition disclosed herein is not particularly limited. For example, the pressure-sensitive adhesive composition or pressure-sensitive adhesive in a form (solvent type) containing a pressure-sensitive adhesive (pressure-sensitive adhesive component) as described above in an organic solvent. Can be a pressure-sensitive adhesive composition in a form dispersed in an aqueous solvent (water-dispersed type, typically an aqueous emulsion type), a hot-melt type pressure-sensitive adhesive composition, and the like. From the viewpoints of coating properties and the degree of freedom in selecting a substrate, a solvent-type or water-dispersed pressure-sensitive adhesive composition can be preferably employed. From the viewpoint of realizing higher adhesive performance, a solvent-type adhesive composition is particularly preferable. Such a solvent-type pressure-sensitive adhesive composition is typically prepared in the form of a solution containing the above-described components in an organic solvent. The organic solvent can be appropriately selected from known or commonly used organic solvents. For example, aromatic compounds such as toluene and xylene (typically aromatic hydrocarbons); acetates such as ethyl acetate and butyl acetate; aliphatic or alicyclic hydrocarbons such as hexane, cyclohexane, and methylcyclohexane Any one solvent selected from the group: halogenated alkanes such as 1,2-dichloroethane; ketones such as methyl ethyl ketone and acetylacetone; and a mixed solvent of two or more. Although not particularly limited, it is usually appropriate to prepare the solvent-based pressure-sensitive adhesive composition to a solid content (NV) of 30 to 65% by mass (for example, 40 to 55% by mass). When NV is too low, the manufacturing cost tends to be high, and when NV is too high, handling properties such as coatability may be lowered.

  As a method for obtaining a pressure-sensitive adhesive sheet from the pressure-sensitive adhesive composition, various conventionally known methods can be applied. For example, a method (direct method) of forming a pressure-sensitive adhesive layer by directly applying (typically applying) the pressure-sensitive adhesive composition to a substrate and drying it can be preferably employed. Further, the pressure-sensitive adhesive composition is applied to a surface having good releasability (for example, the surface of a release liner, the back surface of a release support substrate, etc.) and dried to form a pressure-sensitive adhesive layer on the surface. Alternatively, a method (transfer method) of transferring the pressure-sensitive adhesive layer to the substrate may be employed.

  Application of the pressure-sensitive adhesive composition can be performed using a known or conventional coater such as a gravure roll coater, a reverse roll coater, a kiss roll coater, a dip roll coater, a bar coater, a knife coater, or a spray coater. . From the viewpoint of promoting the crosslinking reaction and improving the production efficiency, the pressure-sensitive adhesive composition is preferably dried under heating. For example, a drying temperature of about 40 ° C. to 150 ° C. (typically 40 ° C. to 120 ° C., for example, 50 ° C. to 120 ° C., further 70 ° C. to 100 ° C.) can be preferably employed. The drying time is not particularly limited, but may be about several tens of seconds to several minutes (for example, within about 5 minutes, preferably about 30 seconds to 2 minutes). The pressure-sensitive adhesive layer is typically formed continuously, but may be formed in a regular or random pattern such as a dot or stripe depending on the purpose and application.

  Although it does not specifically limit, it is preferable that the thickness of an adhesive layer is 10 micrometers or more (for example, 30 micrometers or more, typically 50 micrometers or more) from a viewpoint of exhibiting favorable adhesive force. If the thickness of the pressure-sensitive adhesive layer is too large, productivity and the like tend to decrease. Considering this, it is appropriate that the thickness of the pressure-sensitive adhesive layer is about 300 μm or less (for example, 150 μm or less, typically 100 μm or less). When the pressure-sensitive adhesive sheet disclosed herein has a first pressure-sensitive adhesive layer and a second pressure-sensitive adhesive layer, the first pressure-sensitive adhesive layer that can be disposed on the polishing pad side has a stronger adhesive force. It is preferable to make the thickness of the pressure-sensitive adhesive layer larger than the thickness of the second pressure-sensitive adhesive layer. The ratio (T1 / T2) of the thickness (T1) of the first pressure-sensitive adhesive layer to the thickness (T2) of the second pressure-sensitive adhesive layer is 1.2 or more (for example, 1.5 or more, typically 2 or more). More preferably.

<Base material>
When the technology disclosed herein is applied to a double-sided PSA sheet with a substrate or a single-sided PSA sheet with a substrate, examples of the substrate include a polyethylene (PE) film, a polypropylene (PP) film, and an ethylene-propylene copolymer. Polyolefin film such as film, polyester film such as polyethylene terephthalate (PET) film, plastic film such as polyvinyl chloride film; foam sheet made of foam such as polyurethane foam, polyethylene foam, polychloroprene foam; various fibrous forms Woven and non-woven fabrics (washi, high-quality paper, etc.) made of materials (natural fibers such as hemp and cotton, synthetic fibers such as polyester and vinylon, semi-synthetic fibers such as acetate, etc.) alone or blended ); Aluminum Umuhaku, metal foils such as copper foil; and the like, can be appropriately selected depending on the use of the pressure-sensitive adhesive sheet. As the plastic film (typically a non-porous plastic film, which is a concept distinguished from a woven fabric or a non-woven fabric), any of an unstretched film and a stretched (uniaxially stretched or biaxially stretched) film is used. Can also be used. Further, the surface of the substrate on which the pressure-sensitive adhesive layer is provided may be subjected to surface treatment such as application of a primer and corona discharge treatment. From the viewpoint of workability for attaching to the polishing pad, the substrate is preferably a plastic film (typically a PET film).

  Although the thickness of a base material can be suitably selected according to the objective, generally it is about 10 micrometers-300 micrometers (typically 25 micrometers-100 micrometers) grade. For example, an adhesive sheet using a base material having a thickness in the above range can be easily attached to a larger polishing pad by making use of the rigidity of the base material.

<Total thickness of adhesive sheet>
The total thickness of the pressure-sensitive adhesive sheet (the thickness of the pressure-sensitive adhesive sheet not including the release liner) in the technology disclosed herein is not particularly limited. For example, an adhesive sheet having a thickness of about 20 μm to 500 μm can be used. The thickness of the adhesive sheet may be about 30 μm to 300 μm (for example, 50 μm to 250 μm). The pressure-sensitive adhesive sheet having the above total thickness can be easily attached to a larger polishing pad, for example.

<Release liner>
As the release liner disclosed herein, a conventional release paper or the like can be used, and is not particularly limited. For example, as a substrate for a support (exfoliation treatment target) constituting a release liner, various resin films, papers, fabrics, rubber sheets, foam sheets, metal foil, and composites thereof (for example, A sheet having a laminated structure in which an olefin resin is laminated on both surfaces of paper) can be appropriately selected and used. The release treatment can be performed by a conventional method using a known or commonly used release treatment agent (for example, a release treatment agent such as a silicone-based, fluorine-based, or long-chain alkyl-based release agent). For example, a release liner obtained by treating high-quality paper having PE resin laminated on both sides with a silicone-based release agent can be preferably used. In addition, a low-adhesive substrate such as an olefin resin (for example, PE, PP, ethylene-propylene copolymer, PE / PP mixture), a fluorine-based polymer (for example, polytetrafluoroethylene, polyvinylidene fluoride), The surface of the substrate may be used as a release liner without being subjected to a release treatment. Or you may use what performed the peeling process to this low-adhesive base material. The thickness of the release liner is suitably about 10 μm to 300 μm (for example, 50 μm to 200 μm, typically 60 μm to 160 μm) from the viewpoint of workability and the like.

  Several examples relating to the present invention will be described below, but the present invention is not intended to be limited to those shown in the examples. In the following description, “parts” and “%” are based on mass unless otherwise specified.

<Example 1>
(Preparation of rubber adhesive composition)
100 parts of a styrene isoprene block copolymer (manufactured by Nippon Zeon Co., Ltd., product name “Quintac 3520”, styrene content 15%, diblock body ratio 78%) as a base polymer, and 40 parts of a terpene phenol resin , 30 parts of a terpene resin, 0.75 part of an isocyanate compound (product of Nippon Polyurethane Industry Co., Ltd., product name “Coronate L”), 3 parts of an anti-aging agent, and toluene as a solvent are stirred and mixed. Thus, a rubber pressure-sensitive adhesive composition A having an NV of 50% was prepared.
Here, as the terpene phenol resin, the product name “YS Polystar S145” (softening point 145 ° C., hydroxyl value 100 mgKOH / g) manufactured by Yashara Chemical Co., Ltd. and the product name “YS Polystar T145” (softening point 145 ° C. Two types with a hydroxyl value of 60 mgKOH / g) were used at a mass ratio of 1: 1 so that their total was 40 parts. As the terpene resin, a product name “YS Resin PX1150N” (softening point 115 ° C., hydroxyl value of less than 1 mgKOH / g) manufactured by Yasuhara Chemical Co., Ltd. was used. As an anti-aging agent, the product name “IRGANOX CB612” manufactured by BASF (a blend composition of 2: 1 in a mass ratio of the product name “IRGAFOS 168” manufactured by BASF and the product name “IRGANOX 565” manufactured by the company) is used. used.

(Preparation of acrylic pressure-sensitive adhesive composition A)
An acrylic polymer A was obtained by polymerizing a monomer raw material consisting of 100 parts of butyl acrylate, 5 parts of vinyl acetate, 3 parts of acrylic acid, and 0.1 part of 2-hydroxyethyl acrylate. For 100 parts of acrylic polymer A, as a tackifier, 15 parts of the trade name “Sumilite Resin PR-12603N” (manufactured by Sumitomo Bakelite Co., Ltd.), 10 parts of the trade name “Rekatak PCJ” (manufactured by Harima Chemicals), product The name "Rekatak SE10" (manufactured by Harima Chemicals Co., Ltd.) 10 parts and the product name "M-HDR" (manufactured by Nisshin Hayashi Chemical Industry Co., Ltd., Guangxi) are added, and further, an isocyanate-based crosslinking agent (manufactured by Nippon Polyurethane Industry Co., Ltd. An acrylic pressure-sensitive adhesive composition A was prepared by adding 4 parts of a name “Coronate L”) and toluene to obtain a uniform solution.

(Preparation of adhesive sheet)
A PET film substrate having a thickness of 38 μm was prepared as a substrate. The rubber-based pressure-sensitive adhesive composition A obtained above was applied to the first surface of the base material, followed by drying treatment to form a first pressure-sensitive adhesive layer having a thickness of about 80 μm. A release liner (first release liner) subjected to a release treatment with a silicone release agent was bonded to the first pressure-sensitive adhesive layer. Next, a separate release liner (second release liner) having the same configuration as that of the first release liner is prepared, and the acrylic pressure-sensitive adhesive composition A obtained above is applied to the surface of the second release liner, followed by a drying treatment. The second pressure-sensitive adhesive layer having a thickness of about 40 μm was formed. This second pressure-sensitive adhesive layer side surface was laminated (transferred) onto the second surface (surface opposite to the first surface) of the PET film substrate. In this way, a double-sided PSA sheet according to Example 1 was produced.

<Example 2>
A double-sided pressure-sensitive adhesive sheet according to Example 2 was produced in the same manner as Example 1 except that the thickness of the first pressure-sensitive adhesive layer was changed to 60 μm.

<Example 3>
(Preparation of acrylic pressure-sensitive adhesive composition B)
70 parts of butyl acrylate, 30 parts of 2-ethylhexyl acrylate, 3 parts of acrylic acid, 0.05 part of 4-hydroxybutyl acrylate and 152 parts of toluene as a polymerization solvent were charged into a three-necked flask. After introducing nitrogen gas and stirring for 2 hours to remove oxygen in the polymerization system, 0.08 part of 2,2′-azobisisobutyronitrile (AIBN) was added, and the temperature was raised to 60 ° C. to 6 A time polymerization reaction was carried out. In this way, a polymer solution (a toluene solution of acrylic polymer B) was obtained. To this polymer solution, 30 parts of a tackifier resin (polymerized rosin manufactured by Arakawa Chemical Co., Ltd., trade name “Pencel D125”) and 2 parts of an isocyanate-based crosslinking agent (product of Nippon Polyurethane Industry Co., Ltd., A trade name “Coronate L”) and an appropriate amount of a polymerization solvent were added and stirred sufficiently to prepare a liquid acrylic pressure-sensitive adhesive composition B.

(Preparation of adhesive sheet)
The acrylic pressure-sensitive adhesive composition B obtained above was applied to the first surface of a 75 μm-thick PET film substrate and dried to form a first pressure-sensitive adhesive layer having a thickness of about 70 μm. Otherwise, the double-sided PSA sheet according to Example 3 was prepared in the same manner as Example 1.

<Example 4>
(Preparation of heat-adhesive pressure-sensitive adhesive composition)
50 parts of styrene butadiene styrene block copolymer (SBS) (manufactured by Asahi Kasei Chemicals, trade name “Asaprene T-420”) and 50 parts of SBS (manufactured by Asahi Kasei Chemicals, trade name “Asaprene T-432”), It added to 220 mass parts of toluene as a solvent, and stirred for about 30 minutes until SBS melt | dissolved. To the obtained mixed solution, 100 parts of a tackifier resin (a tackifier resin mainly composed of an alicyclic saturated hydrocarbon resin manufactured by Arakawa Chemical Industry Co., Ltd., trade name “Arcon M115”) and a tackifier resin (HERCULES) By adding 20 parts of a tackifying resin having a vinyltoluene-methylstyrene copolymer as a main component, trade name “Picotex # 120”), and stirring for about 30 minutes until the tackifying resin is dissolved. A mixed solution in which SBS and tackifying resin were dissolved was obtained.

  Also, 2 parts of an antioxidant (trade name “NOCRACK NS-6” manufactured by Ouchi Shinsei Chemical Co., Ltd.) and 1 part of an antioxidant (trade name “NOCRACK MB” manufactured by Ouchi Shinsei Chemical Industry Co., Ltd.) The mixture was added to 8 parts of isopropyl alcohol as a solvent, and stirred for several minutes to disperse the antioxidant in the solvent. The obtained antioxidant solution was added to the mixed solution in which the SBS and tackifying resin were dissolved, and the mixture was stirred for about 60 minutes. In this way, a solution of the heat-adhesive pressure-sensitive adhesive composition according to Example 4 was obtained.

(Preparation of adhesive sheet)
The heat-adhesive pressure-sensitive adhesive composition obtained above was applied to the first surface of a PET film substrate having a thickness of 75 μm, and dried to form a first pressure-sensitive adhesive layer having a thickness of 80 μm. Moreover, the thickness of the 2nd adhesive layer was 40 micrometers. Otherwise, the double-sided PSA sheet according to Example 4 was prepared in the same manner as Example 1.

<Example 5>
A PET film substrate having a thickness of 75 μm was used as the substrate. Otherwise, the double-sided PSA sheet according to this example was prepared in the same manner as in Example 2.

<Example 6>
As an aromatic petroleum resin, a product name “Nisseki Neopolymer 150” (softening point 155 ° C., hydroxyl value of less than 1 mg KOH / g) manufactured by JX Nippon Oil & Energy is further added to 100 parts of the base polymer. The rubber-based pressure-sensitive adhesive composition B was prepared in the same manner as the rubber-based pressure-sensitive adhesive composition A of Example 1. A double-sided pressure-sensitive adhesive sheet according to this example was prepared in the same manner as in Example 5 except that the rubber-based pressure-sensitive adhesive composition B was used to form the first pressure-sensitive adhesive layer (thickness: 60 μm).

[180 degree peel strength to stainless steel sheet (vs. SUS adhesive strength)]
A PET film having a thickness of 25 μm was bonded to the second adhesive surface (adhesive surface of the second adhesive layer) of the double-sided pressure-sensitive adhesive sheet according to Examples 1 to 4, and this was cut into a size having a width of 25 mm and a length of 100 mm. A sample was made. In an environment of 23 ° C. and 50% RH, the first adhesive surface of the measurement sample (adhesive surface of the first adhesive layer) is exposed, and a 2 kg roller is attached to the surface of the adherend. It was reciprocated once and crimped. After leaving this in the same environment for 30 minutes, using a universal tensile and compression tester (device name “Tensile and compression tester, TCM-1kNB” manufactured by Minebea Co., Ltd.), in accordance with JIS Z0237, a peeling angle of 180 degrees, The peel strength was measured under the condition of a tensile speed of 300 mm / min. The peel strength per 20 mm width (N / 20 mm width) was calculated by converting the measured value into a 20 mm width value (× 20 mm / 25 mm). A stainless steel plate (SUS304 plate) was used as the adherend. The measurement was performed 3 times and the average value was recorded. The results are shown in Table 1.

[Adhesive strength after immersion in NaOH aqueous solution]
A PET film having a thickness of 25 μm was bonded to the second adhesive surface (adhesive surface of the second adhesive layer) of the double-sided pressure-sensitive adhesive sheet according to Examples 1 and 2, and this was cut into a size having a width of 25 mm and a length of 100 mm. A sample was made. In an environment of 23 ° C. and 50% RH, the first adhesive surface (adhesive surface of the first adhesive layer) of the measurement sample is exposed, and the first adhesive surface is a stainless steel plate (SUS304 plate) as an adherend. And 2 kg of rollers were reciprocated once on the surface. This measurement sample was immersed in an aqueous NaOH solution adjusted to pH 11 at 50 ° C. for 3 days. After removing the measurement sample from the aqueous solution and washing with water, the moisture was wiped off, and the peel strength (under the peel angle of 180 degrees and the tensile speed of 300 mm / min in accordance with JIS Z0237, similar to the above SUS adhesive strength) N / 20 mm width). The measurement was performed 3 times and the average value was recorded. The results are shown in Table 1 as NaOH adhesion after immersion in SUS.

[180 degree peel strength against polishing pad (by temperature)]
A PET film having a thickness of 25 μm was bonded to the second adhesive surface (adhesive surface of the second adhesive layer) of the double-sided adhesive sheet according to Example 5 and Example 6, and this was cut into a size of 25 mm in width and 100 mm in length. A measurement sample was prepared. In an environment of 23 ° C. and 50% RH, the first adhesive surface of the measurement sample (adhesive surface of the first adhesive layer) is exposed, and a 2 kg roller is attached to the surface of the adherend. It was reciprocated once and crimped. This was left for 1 hour in each temperature atmosphere shown in Table 2 (23 ° C., 40 ° C., 60 ° C., 80 ° C.), and then a universal tensile compression tester (device name “tensile compression tester, TCM-1kNB” Minebea) The peel strength (N / 25 mm width) was measured according to JIS Z0237 under the conditions of a peel angle of 180 degrees and a tensile speed of 300 mm / min. As the adherend, a commercially available polishing pad (hard urethane polishing pad) was used. The measurement was performed three times, and the average value was recorded as the adhesive strength against the polishing pad. The results are shown in Table 2.

[Shearing adhesive strength to polishing pad (by temperature)]
The double-sided PSA sheet according to Example 5 and Example 6 was cut into a size of 20 mm × 20 mm to prepare a measurement sample. In the environment of 23 ° C. and 50% RH, the first adhesive surface (adhesive surface of the first adhesive layer) of the measurement sample was placed on the surface of a commercially available polishing pad (hard urethane polishing pad), and the above measurement was performed. The second adhesive surface of the sample (adhesive surface of the second adhesive layer) was placed on the surface of a stainless steel plate (30 mm × 100 mm × 0.1 mm thickness), and a 5 kg roller was reciprocated once for pressure bonding. This was left for 1 hour in each temperature atmosphere shown in Table 2 (23 ° C., 40 ° C., 60 ° C., 80 ° C.), and then a universal tensile compression tester (device name “tensile compression tester, TCM-1kNB” Minebea) The maximum strength at that time was recorded as the shear adhesive strength (N) against the polishing pad. Specifically, as shown in FIG. 5, the first adhesive surface 100B of the measurement sample 100 is bonded to the polishing pad 202, and the second adhesive surface 100A of the measurement sample 100 is bonded to the stainless steel plate 201 and bonded under the above conditions. did. This was left for 1 hour in the above temperature atmosphere, and then pulled in the direction of the arrow in FIG. 5 (that is, the shear direction) at the above speed, and the peel strength (N) per 20 mm × 20 mm was measured. The measurement was performed 3 times and the average value was recorded. The results are shown in Table 2.

  As shown in Table 1, the pressure-sensitive adhesive sheets according to Examples 1 and 2 showed high adhesive strength with respect to SUS of 30 N / 20 mm or more. From this result, it is considered that the pressure-sensitive adhesive sheets according to Examples 1 and 2 are firmly bonded to a polishing pad (for example, a polyurethane foam polishing pad). In addition, the pressure-sensitive adhesive sheets according to Examples 1 and 2 exhibited a SUS adhesive strength of 30 N / 20 mm or more (specifically, 45 N / 20 mm or more) after immersion in a NaOH aqueous solution. That is, these pressure-sensitive adhesive sheets are excellent in chemical resistance (specifically, alkali resistance), and are considered to continuously exhibit excellent pressure-sensitive adhesive force even in an environment exposed to an alkaline polishing liquid, for example. From the above, it can be said that the pressure-sensitive adhesive sheets according to Examples 1 and 2 are pressure-sensitive adhesive sheets particularly suitable for polishing pad fixing applications.

As shown in Table 2, the pressure-sensitive adhesive sheets according to Examples 5 and 6 are strong against a polishing pad (specifically, a hard urethane polishing pad) in a wide temperature range from room temperature to high temperature. Adhesion was shown. In particular, in Example 6 using a tackifying resin (specifically, an aromatic petroleum resin) corresponding to the tackifying resins T _HR1 and T _HR2 , the adhesive strength of the polishing pad was improved in a wide temperature range including a high temperature region. The temperature dependency was small, and high shear adhesive strength was exhibited at all measurement temperatures. From these results, the pressure-sensitive adhesive sheet using the pressure-sensitive adhesive _THR1 or _THR2 disposed on the polishing pad side firmly and stably fixes the polishing pad against temperature changes during polishing. I know you get.
From the above, it can be said that the pressure-sensitive adhesive sheet disclosed herein is a pressure-sensitive adhesive sheet particularly suitable for polishing pad fixing.

  Specific examples of the present invention have been described in detail above, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above.

1, 2, 3 Adhesive Sheet 11 First Adhesive Layer 11A First Adhesive Surface 12 Second Adhesive Layer 12A Second Adhesive Surface 15 Base Material 21, 22 Release Liner 30 Polishing Pad 40 Polishing Device 50 Polishing Device Surface Plate

Claims (8)

A pressure-sensitive adhesive sheet for fixing a polishing pad,
Comprising an adhesive layer constituting the adhesive surface of the adhesive sheet;
The pressure-sensitive adhesive surface is a pressure-sensitive adhesive sheet having a 180 degree peel strength of 30 N / 20 mm or more with respect to a stainless steel plate.   The pressure-sensitive adhesive layer according to claim 1, wherein the pressure-sensitive adhesive layer contains a block copolymer of a monovinyl-substituted aromatic compound and a conjugated diene compound as a base polymer.   The pressure-sensitive adhesive sheet according to claim 2, wherein the base polymer is a styrenic block copolymer. The pressure-sensitive adhesive layer contains a tackifying resin,
The pressure-sensitive adhesive sheet according to any one of claims 1 to 3, wherein the tackifying resin contains a high softening point resin having a softening point of 120 ° C or higher.   The pressure-sensitive adhesive sheet according to claim 4, wherein the high softening point resin includes a terpene phenol resin.   The pressure-sensitive adhesive sheet according to claim 4 or 5, wherein the tackifying resin contains a low softening point resin having a softening point of less than 120 ° C.   Both surfaces provided with a base material, a first pressure-sensitive adhesive layer as the pressure-sensitive adhesive layer provided on one surface of the base material, and a second pressure-sensitive adhesive layer provided on the other surface of the base material The adhesive sheet as described in any one of Claims 1-6 comprised as an adhesive sheet.   The pressure-sensitive adhesive sheet according to claim 7, wherein the pressure-sensitive adhesive surface of the first pressure-sensitive adhesive layer is bonded to a polishing pad, and the pressure-sensitive adhesive surface of the second pressure-sensitive adhesive layer is bonded to a polishing apparatus surface plate.

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